Inside the second: Gaming performance with today's CPUs

Does the processor you choose still matter?by Scott Wasson  4:16 PM on August 23, 2012

As you may know, a while back, we came to some difficult realizations about the validity of our methods for testing PC gaming performance. In my article Inside the second: A new look at game benchmarking, we explained why the widely used frames-per-second averages tend to obscure some of the most important information about how smoothly a game plays on a given system. In a nutshell, the problem is that FPS averages summarize performance over a relatively long span of time. It's quite possible to have lots of slowdowns and performance hiccups during the period in question and still end up with an average frame rate that seems quite good. In other words, the FPS averages we (and everyone else) had been dishing out to readers for years weren't very helpful—and were potentially misleading.

To sidestep this shortcoming, we proposed a new approach, borrowed from the world of server benchmarking, that focuses on the actual problem at hand: frame latencies. By considering the time required to render each and every frame of a gameplay session and finding ways to quantify the slowdowns, we figured we could provide a more accurate sense of true gaming performance—not just the ability to crank out lots of frames for high averages, but the more crucial ability to deliver frames on time consistently.

Some good things have happened since we proposed our new methods. We've deployed them in a host of graphics card reviews, and they have proved their worth, helping to uncover some performance deficiencies that would have otherwise remained hidden. In response to your feedback, we've refined our means of quantifying the latency picture and presenting the info visually. A few other publications have noticed what we're doing and adjusted their own testing methods; even more have quietly inquired about the possibility behind the scenes.

Most importantly, you, our readers, have responded very positively to the changes, even though we've produced some articles that are much more demanding reading than your average scan-and-skip-to-the-conclusion PC hardware review.

We have largely missed one important consequence of our insights, though. Latency-focused game testing doesn't just apply to graphics cards; it's just as helpful for considering CPU performance. We made a quick down payment on exploring this matter in our Ivy Bridge review, but we haven't done enough to pursue it. Happily, that oversight ends today. Over the summer, we've tested 18 different PC processors from multiple generations in a range of games, and we can now share the results with you.

Before your eyes glaze over from the prospect of data overload, listen up. The results we've compiled confront a popular myth: that PC processors are now so fast that just about any CPU will suffice for today's games, especially since so many titles are console ports. I've said something to that effect myself more than once. But is it true? We now have the tools at our disposal to find out. You may be surprised by what we've discovered.

The contenders
Yes, we really have tested 18 different desktop CPUs for this article. They break down into several different classes, delineated mainly by price. We have a full complement of the latest chips on hand, including several members of Intel's Ivy Bridge lineup and a trio of AMD FX processors. We've tested them against their predecessors in the past generation or two, to cover a pretty big swath of the CPUs sold in the past several years. Allow me to make some brief introductions.

Quite a few PC enthusiasts will be interested in the first class of CPUs tested, which is headlined by the Core i5-3470 at $184. This Ivy Bridge-based quad-core replaces the Sandy Bridge-derived Core i5-2400 at the same price. The newer chip has slightly faster clocks and a lower power envelope—77W instead of 95W—versus the model it supplants. Two generations back, this price range was served by the Core i5-655K, a dual-core chip. The closest competing offering from AMD is the FX-6200 at $155, a six-core part based on the Bulldozer architecture. The FX-6200's precursor was the Phenom II X4 980, which we've also invited to the festivities.

For a little more money, the next class of CPUs promises even higher performance. Intel's Ivy Bridge offering in this range is the Core i5-3570K for $216, with a fully unlocked multiplier to ease overclocking. The 3570K replaces an enthusiast favorite, the Core i5-2500K, again with slightly higher clock speeds and a lower thermal design power (or TDP). This is also the space where AMD's top Bulldozer chip, the FX-8150, contends. The legacy options here are a couple of 45-nm chips, the Core i5-760 and the Phenom II X6 1100T.

More relevant for many of us mere mortals, perhaps, are the lower-end chips that sell for closer to a hundred bucks. AMD's FX-4170 at $135 gets top billing here, since our selection of Intel chips skews to the high end. We think the FX-4170 is a somewhat notable entry in the FX lineup because it boasts the highest base and Turbo clock speeds, even though it has fewer cores. The FX-4170 supplants a lineup of chips known for their strong value, the Athlon II X4 series. Our legacy representative from that series actually bears the Phenom name, but under the covers, the Phenom II X4 850 employs the same silicon with slightly higher clocks.

Finally, we have the high-end chips, a segment dominated by Intel in recent years. We've already reviewed the Ivy-derived Core i7-3770K, a $332 part that inherits the spot previously occupied by the Core i7-2600K and, before that, by the Core i7-875K. Also kicking around in the same price range is the Core i7-3820, a fairly affordable Sandy Bridge-E-based part that drops into Intel's pricey X79 platform. The Core i7-3820's big brother is a thousand-dollar killer, the Core i7-3960X, the fastest desktop CPU ever.

This selection isn't perfect, but we think it provides a good cross-section of the market. Face it: the CPU makers offer way too many models these days. The sheer volume of parts is difficult to track without an online reference. If you're having trouble keeping them sorted, fear not. We've broken down the results by class in the following pages, and we'll summarize the overall picture with one of our famous price-performance scatter plots.